The present invention relates generally to medical devices and methods, and more particularly to devices and methods for forming connections or facilitating flow between openings formed in adjacently situated anatomical conduits.
In modem medical practice, it is sometimes desirable to form flow-through connections (e.g., passageways or flow channels) between adjacent anatomical conduits (natural or prosthetic), or between adjacent segments of a single anatomical conduit. The types of natural and prosthetic anatomical and conduit(s) which may be linked by such flow-through connections include; blood vessels, vas deferens, fallopian tubes, intestines, lymphatic ducts, grafts, etc.
In particular, U.S. patent application Ser. Nos. 08/730,327 and 08/730,496 have described certain methods and devices for performing transluminal, catheter-based, bypass procedures wherein flow-through connections are formed between two adjacently situated anatomical conduits (e.g., blood vessels) to bypass a diseased, injured or obstructed segment of one of those anatomical conduits, using a segment of the adjacent conduit as the bypass loop. These procedures include catheter based, transluminal, in situ coronary vein bypass procedures wherein at least one primary flow-through connection (i.e., bloodflow passageways) is formed between an obstructed coronary artery and an adjacent coronary vein, such that blood will flow from the obstructed artery into the adjacent coronary vein. The arterial blood which has flowed into the coronary vein may then be allowed to retroperfuse the ischemic myocardium by retrograde flow through the coronary vein. Or, alternatively, one or more secondary flow-through connections may be formed between the coronary vein and the obstructed artery at site(s) downstream of the obstruction (or some other coronary artery), thereby allowing the arterial blood which had flowed into the coronary vein to reenter the obstructed artery (or some other coronary artery), after having bypassed the arterial obstruction.
Also, International Patent Publication No. WO 97/27897 describes certain thoracoscopic or minimally invasive methods for by-passing an obstructed coronary artery by maneuvering, into juxtaposition with the obstructed artery, a tubular graft. Openings are formed in the juxtapositioned graft and in the adjacent artery, at sites upstream and downstream of the obstruction. The graft is then connected to the artery such that the openings in the graft are positioned in alignment with, and in fluidic connection with, the openings in the artery. Blood may then flow through the flowthrough connections between the tube graft and the artery, thereby bypassing an obstructed region of the artery.
Additionally, U.S. Pat. No. 3,042,021 (Read), entitled Bypass Type Insert Plug For Body Passageway, describes a procedure wherein an apparatus is used to connect or facilitate flow between openings formed in adjacent anatomical passageways (e.g., genitourinary ducts), which are situated in side-to-side juxtaposition.
Also, U.S. Pat. No. 5,443,497 (Venbrux), entitled Purcutaneous Prosthetic ByPass Graft and Method of Use, describes a device for bypassing an occluded lumen or for coupling two lumens, and related methods for installing such device(s) within the body.
At least some of the previously described procedures for forming flow-through connections (e.g., passageways or flow channels) between adjacent anatomical conduits may be accomplished by a transluminal, catheter-based approach which avoids the need for open surgical exposure and dissection of the involved anatomical passageways. Such transluminal procedures generally require the passage of a flexible cannula or catheter through the lumen of one of the involved body passageways, deploying or actuating a tissue penetration element from the catheter, through the wall of the passageway in which the catheter is positioned, and into the adjacent passageway to which the side to side connection is to be made. In at least some of these transluminal, catheter-based procedures, it is additionally desirable to install a connector apparatus to maintain the desired alignment of the flow-through openings in the adjacent anatomical conduits, and/or to prevent the leakage of body fluid into the surrounding tissues or spaces. Some connector apparatus of this type have previously been described in U.S. patent application Ser. Nos. 08/730,327 and 08/730,496 as well as International Patent Publication No. WO 97/27898 entitled xe2x80x9cMethods and Apparatus for Connecting Openings Formed in Adjacent Blood Vessels or Other Anatomical Conduitsxe2x80x9d. However, none of these previously described methods or apparatus appear to be of optimal design for all clinical applications.
Accordingly, there exists a need in the art for the design and development of new apparatus for connecting or maintaining alignment of flow-through openings formed in adjacent blood vessels or other anatomical conduits. It is further desirable that such connector apparatus be implantable by a transluminal, catheter-based technique to avoid the need for open surgical exposure of the affected anatomical conduits.
The present invention includes devices and methods for connecting, or facilitating flow between, adjacently situated anatomical or prosthetic conduit(s) (e.g., openings in separate anatomical conduits or two openings at different locations in the same anatomical conduit). The connector devices of the present invention include certain xe2x80x9ctwo-annular-memberxe2x80x9d embodiments and xe2x80x9cthree-annular-memberxe2x80x9d embodiments, as described more fully herebelow.
In accordance with the invention, there is provided a two-annular-member connector device which is implantable within the body of a mammal to facilitate flow between (i.e, to maintain alignment and/or connection between) a first opening formed in an anatomical conduit (e.g., a first blood vessel), and a second opening formed in an anatomical conduit (e.g., an opening formed in a second blood vessel or a second opening formed in the first blood vessel). This two-annular-member connector device generally comprises (a) at least one proximal radially expandable annular member, (b) at least one distal radial expandable annular member, (c) at least one strut member connected to and extending between the proximal and distal annular members. Prior to implantation in the body, this two-annular-member connector device is disposed in a collapsed disposition with its proximal and distal annular members in their radially collapsed configurations and its strut member(s) in a pre-expansion configuration. In this collapsed disposition, the connector device is sufficiently compact to be mounted upon or within a delivery catheter which is transluminally advancable to site of intended implantation. After the delivery catheter has been transluminally advanced to the site of intended implantation, the connector device is released or separated from the delivery catheter, its proximal and distal annular members are expanded to their radially expanded configurations, and its strut member(s) caused or permitted to assume a post-expansion (i.e., curved) configuration. In this manner the connector device may be implanted with its proximal annular member(s) at a first location in an anatomical or prosthetic conduit (e.g., a first blood vessel), its distal annular member(s) at a second location in an anatomical or prosthetic conduit (e.g., a second blood vessel or a second location within the first blood vessel), and its strut member(s) extending therebetween. When so implanted, the two-annular-member connector device may serve to maintain the patency, alignment and/or approximation of the first and second openingsxe2x80x94and of any interstitial tunnel, passageway or bypass conduit created or disposed between such openings.
Further in accordance with the invention, there is provided a three-annular-member connector device which is implantable within the body of a mammal to facilitate flow between (i.e, to maintain alignment and/or connection between) a first opening formed in an anatomical conduit (e.g., a first blood vessel), and a second opening formed in an anatomical conduit (e.g., an opening formed in a second blood vessel or a second opening formed in the first blood vessel). This three-annular-member connector device generally comprises (a) at least one proximal radially expandable annular member, (b) at least one distal radially expandable annular member, (c) at least one medial radially expandable annular member, (d) at least one first strut member connected to and extending between the proximal and medial annular members, and (e) at least one second strut member connected to and extending between the medial and distal annular members. This device is initially mountable upon or in a deliver catheter while in a collapsed disposition wherein the proximal, distal and medial annular members are in radially compact configurations and the strut members are in xe2x80x9cpre-expansionxe2x80x9d configurations. Thereafter the device is transitioned to an implantation disposition wherein the proximal, distal and medial annular members are in their radially expanded configurations and the strut member(s) are in their xe2x80x9cpost-expansionxe2x80x9d (e.g., curved) configurations. This results in the connector device being implanted with its proximal annular member(s) at a first location in an anatomical or prosthetic conduit (e.g., within a first blood vessel), its distal annular member(s) at a second location in an anatomical or prosthetic conduit (e.g., within a second blood vessel or a second location within the first blood vessel), and its medial annular member(s) located within or between the first and second openings of the anatomical or prosthetic conduit(s). When so implanted, the three-annular-member connector device may serve to maintain the patency, alignment and/or approximation of the first and second openingsxe2x80x94and of any interstitial tunnel, passageway or bypass conduit created or disposed between such openings.
Still further in accordance with the invention, in either the two-annular-member or three-annular-member connector devices, the actual number of annular members present (i.e., in excess of two (2) or three (3)) may be determined by functional considerations, such as the amount of scaffolding of support required to maintain the desired patency and approximation of the flow channels, and/or the specific position at which the device is to be implanted within the body.
Still further in accordance with the invention, any embodiment of the connector device of the present invention may be fully or partially covered by a pliable covering (e.g., woven polyester, expanded polytetrafluoroethylene (ePTFE), polyurethane, etc.) to channel, direct, block, or otherwise control the flow of body fluid and/or to improve the biological compatibility of the connector device. Additionally or alternatively, such covering may be formed of material which will promote or prevent proliferation of the adjacent tissue. In some applications, the covering may be formed of material which will biodegrade or become absorbed after it has served its intended purpose. Flow through holes or openings may be formed at selected locations in such pliable covering to direct or permit the desired flow of body fluid through the device. Such flow-through holes or openings may be formed in the covering prior to implantation of the connector device, or may be formed in situ following implantation of the connector device.
Still further in accordance with the present invention, the annular members and/or strut member(s) of the connector devices may be formed of a resilient material which is initially compressible and constrainable such that the annular members are in their radially collapsed states and the strut member(s) are in their pre-expansion configurations but which, when unconstrained, will self-expand to a configuration wherein the annular members are expanded and the strut member(s) are in their post-expansion configurations. Alternatively, the annular members and/or strut member(s) of the connector devices may be formed of a malleable (e.g., plastically deformable) material which is initially formed such that the annular members are in their radially collapsed states and the strut member(s) are in their pre-expansion configurations but which, when outward radial pressure is exerted thereagainst, will plastically deform to a configuration wherein the annular members are expanded and the strut member(s) are in their post-expansion configurations.
Still further in accordance with the invention, the connector devices may be implanted in various different orientations or arrangements and/or my be purposely formed or deformed in a manner which will exert a traction force upon the surrounding tissue. Such traction force may be utilized to cause sloping or curvature of the openings formed in the first and second anatomical conduits and/or any surrounding tissue, to promote non-turbulent, laminar flow of blood or other body fluid between the anatomical conduits. In this regard, the invention includes methods (described in detail herebelow), for placing the connector devices in opposing orientations so as to cause two (2) adjacent interstitial passageways to angle or slope toward one another to promote non-turbulent flow therethrough.
Further aspects and advantages of the present invention will be apparent to those skilled in the art, after reading and understanding the detailed description of preferred embodiments set forth herebelow, and after viewing the accompanying drawings.